The present invention relates generally to the investment casting art, and more specifically to one-piece refractory molds made by the lost pattern process of investment casting.
The lost pattern process of investment casting is typically carried out using a pattern assembly comprised of a group of casting patterns made of wax or similar material so that they can be melted out of the mold. The patterns are attached to a sprue member or center tree to form a casting system known as a "set-up". A pouring cup member is frequently attached to one end of the sprue member.
The set-up is coated or invested with refractory material to form a ceramic shell mold or a bulk investment mold. The set-up is then removed from the mold by a procedure which typically involves melting out the patterns, as in a furnace or an autoclave, to form the pattern cavities. The resulting mold is characterized by a casting system comprising a sprue passage, a pouring cup at one end of the sprue passage, and casting cavities gated into the passage. During casting the molten metal is introduced directly into the sprue passage from the pouring cup. As the metal rises in the sprue passage, it gradually fills the connected pattern cavities.